Yes, you do need a BluRay player for a BluRay disc. Generally, these have only HDMI output, so you will need a modern AVR or prepro and, if you want the Atmos tracks, it will have to be capable of decoding Atmos. OTOH, there may be other audio formats on the disc and, since you have "a standard stereo setup," those formats may suffice, especially if the BluRay player has an analog stereo or S/PDIF output.